For effective solutions, understanding the mycotoxin threat is key. Mycotoxins in feed pose a serious threat to poultry health and performance. However, the level of threat, differences in toxicity and impact on productivity remain less well understood. Let’s have a look at mycotoxins in the poultry industry.
With the knowledge that mycotoxins are eating away at poultry operation profits, there has also been a surge in the development and availability of in-feed solutions to the mycotoxin challenge. Although to date most have taken a one-size-fits-all approach that simply adjusts dose rate to bodyweight for each livestock species. This is now changing, however, following the emergence of a strong rationale for mycotoxin solutions that target the specific mycotoxin threat and physiological differences of each individual species. For the poultry industry, for example, the Aspergillus mycotoxin aflatoxin (AFB1) remains the greatest threat, with poultry more susceptible to AFB1 ingestion than any other livestock species.
Mycotoxins first came under the spotlight in 1960 when the so-called ‘Turkey X Syndrome’ outbreak was traced to the presence of AFB1 in turkey feed. Since then, many additional mycotoxins have been identified, though AFB1 remains of primary concern to the poultry industry.
The mycotoxins produced by Aspergillus moulds – which includes the ochratoxins (OTA) as well as AFB1 – regularly develop during the storage of feeds and feed ingredients, as well as infecting growing crops. Any time feeds are exposed to moisture, the risk of Aspergillus growth is increased. With many key monogastric feed ingredients produced in regions of the world known to suffer from high humidity, the risk of OTA and AFB1 contamination can be considered to be permanently high.
Other symptoms of the Fusarium mycotoxins include increased embryonic mortality and diarrhoea, plus reduced hatchability, feed intakes and body weight gain.
It means that although poultry are typically considered to be relatively resistant to the Fusarium mycotoxins, the potential threat should not be overlooked.
Even low levels of DON and T2 toxin, for example, are known to damage the lining of the small intestine and reduce nutrient absorption. This has the potential to negatively affect feed conversion efficiency, feed intakes and liveweight gain.
There is even some evidence to suggest that certain mycotoxins can predispose poultry to other diseases, such as Clostridium perfringens-induced necrotic enteritis and coccidiosis, leading to reduced growth rates, poorer feed conversion and higher mortality.
However, it is the Aspergillus mycotoxins that remain the top priority. AFB1 is a carcinogenic compound that is known to affect gene regulation and metabolism at the cellular level – symptoms include liver damage, development of fatty liver, immune suppression and reduced growth rates – whilst OTA is associated with renal dysfunction and kidney damage, and is reported to affect weight gain, feed intakes and immune function. Both can cause increased mortality where levels of exposure are high.
It should be no surprise, therefore that the use of in-feed mycotoxin deactivators and binders to protect bird health and productivity has increased markedly in recent years. The most common approach is to use clay minerals or yeast cell walls to bind with the mycotoxins, though efficacy varies depending on the mycotoxin and is typically more effective against AFB1 and less so against Fusarium mycotoxins.
The ability to maintain efficacy within the pH range typically found in the bird’s gastro-intestinal tract (pH 3-7) is also critical to success, and can vary considerably between different binders (Figure 2).